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2 years ago

12

Which of the following describes an accelerated motion

1 answer:

Naily [24]2 years ago

3 0

Accelerated motion such as a vehicle (car) or a moving item such as a (football thrown in the air)

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A force of F = (2.00ˆi + 3.00ˆj) N is applied to an object that is pivoted about a fixed axle aligned along the z coordinate axi

Vladimir [108]

Explanation:

It is given that,

Force applied to object, $F=(2i+3j)\ N$

Position, $r=(4i+5j)\ m$

(b) The cross product of force and position vector is used to find the net torque about the z axis. It is given by :

$\tau=F\times r$

$\tau=(2i+3j) \times (4i+5j)$

$\tau=\begin{pmatrix}0&0&-2\end{pmatrix}$

or

$\tau=(-2k)\ N-m$

The torque is acting in -z axis.

(a) The magnitude of torque is given by :

$|\tau|=\sqrt{(-2)^2}$

$|\tau|=2\ N-m$

Hence, this is the required solution.

5 0

3 years ago

A cord is used to vertically lower an initially stationary block of mass M = 3.6 kg at a constant downward acceleration of g/7.

dalvyx [7]

Answer:

(a) $W_c=127.008 J$

(b) $W_g=148.176 J$

(c) K.E. = 21.168 J

(d) $v=3.4293m.s^{-1}$

Explanation:

Given:

mass of a block, M = 3.6 kg

initial velocity of the block, $u=0 m.s^{-1}$

constant downward acceleration, $a_d= \frac{g}{7}$

$\Rightarrow$ That a constant upward acceleration of $\frac{6g}{7}$ is applied in the presence of gravity.

∴ $a=- \frac{6g}{7}$

height through which the block falls, d = 4.2 m

(a)

Force by the cord on the block,

$F_c= M\times a$

$F_c=3.6\times (-6)\times\frac{9.8}{7}$

$F_c=-30.24 N$

∴Work by the cord on the block,

$W_c= F_c\times d$

$W_c= -30.24\times 4.2$

We take -ve sign because the direction of force and the displacement are opposite to each other.

$W_c=-127.008 J$

(b)

Force on the block due to gravity:

$F_g= M.g$

∵the gravity is naturally a constant and we cannot change it

$F_g=3.6\times 9.8$

$F_g=35.28 N$

∴Work by the gravity on the block,

$W_g=F_g\times d$

$W_g=35.28\times 4.2$

$W_g=148.176 J$

(c)

Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.

mathematically:

$K.E.= W_g+W_c$

$K.E.=148.176-127.008$

K.E. = 21.168 J

(d)

From the equation of motion:

$v^2=u^2+2a_d\times d$

putting the respective values:

$v=\sqrt{0^2+2\times \frac{9.8}{7}\times 4.2 }$

$v=3.4293m.s^{-1}$ is the speed when the block has fallen 4.2 meters.

6 0

3 years ago

Consider the following list of numbers. 129, 685, 125, 511, 601, 52, 46 The height of a binary search tree is the maximum number

NemiM [27]

Answer:

The height of the tree is three (3) deep

Explanation:

It's 3 deep

Under 129, comes 125 and 685;

Under 125, comes 52 : Under 685, comes 511;

Under 52, comes 46 : Under 511, is 601.

This is illustrated below.

129

∧

125,685

|,|

52,511

|,|

46,601

5 0

3 years ago

Describe a situation where you could properly conclude that a set of data is precise but

Orlov [11]

It’s not arrested because if you look closer it’s plug walk I don’t even understand how it talk tho

4 0

2 years ago

Which weather condition commonly occurs along a cold front

aleksklad [387]

Precipitation is your answer. according to my science textbook, in a cold front, warm air and cold air interact and cause precipitation.

7 0

3 years ago

Read 2 more answers